A variety of effective interventions exist for people who seek help for depression. However, there is a lack of effective interventions for individuals who do not seek help or follow through with treatment referrals. We propose to fill this gap in services by developing and testing a Transtheoretical Model-based intervention that will be delivered proactively, on a population basis, to primary care patients who are experiencing symptoms of depression but are not currently involved in treatment. It is the first intervention for depression that is appropriate for individuals in all stages of change-not merely the minority who are prepared to take action. In Phase I of this Fast Track Initiative, the aims are to norm TTM measures, develop the TTM interventions, and determine the feasibility of this approach by assessing study recruitment rates and reactions to the intervention materials. Primary care patients who screen positive for mild to moderate depression and are not involved in treatment will complete surveys for measurement norming (n=100) or participate in a pilot-test of the intervention materials (n=50). If feasibility conditions are met, we will conduct a randomized clinical trial in Phase II to assess the efficacy of the expert system intervention for depression. PROPOSED COMMERCIAL APPLICATIONS: Depression is a costly illness for health care organizations, disability insurers, and employers because of increased health service utilization, disability claims, and lost productively among depressed individuals. An effective, low-cost expert system that can reduce the prevalence of depression on a population basis has significant commercial potential.